excessive valve clearance
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wengr
excessive valve clearance
Hello, is it ok to run an engine with valve clearances around .030"? I thought I could check my clearances, order shims and put the new ones in when the head was reassembled, but the clearances are all big at around .030. Lesson learned. I guess all cambox gaskets are not equal thickness or? So I guess I have to do them again, with the cams in place. So can I start and run it in the meantime without damage or must they be done immediately?
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narfire
- Posts: 3959
- Joined: Sat Dec 27, 2008 2:14 am
- Your car is a: 1980 124 spider
- Location: Naramata B.C.
Re: excessive valve clearance
Holy S... thats almost double what the specs are. Is the head off or on the engine? I was told just today from an old time fiat and volvo mechanic(my shim supply to 4.45 mm) that too much clearance will make a racket that will be easy to hear . I have to order some shims that I thought were quite thick 4.65 mm and 4.55mm but he said stick to spec. clearances if you can when I asked about a thinner shim.
I hope someone else chimes in but if I get this right, a high clearance will have the valve open late and close early. A while back I had lousy compression in 3 cylinders and after re doing the shims to spec,the compession was great and seemed to have a bit more pull.
After all that, I'd stick to spec and do the adjusting just the once.
Chris
I hope someone else chimes in but if I get this right, a high clearance will have the valve open late and close early. A while back I had lousy compression in 3 cylinders and after re doing the shims to spec,the compession was great and seemed to have a bit more pull.
After all that, I'd stick to spec and do the adjusting just the once.
Chris
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
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wengr
Re: excessive valve clearance
the head is off. iirc my shop manual specs are .018 to .021. I know it has to be put to spec. but now I see that it has to be done with the cam boxes staying put, which means I'll need the special tool to depress the tappets. I don't have it so what I'm wondering is if I can put the car back together and run it some to continue working on it in the meantime or if damage will result from the excessive clearances?
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manoa matt
- Posts: 3442
- Joined: Thu Oct 26, 2006 4:28 pm
- Your car is a: 1978 Fiat 124 Spider 1800
- Location: Honolulu, Hawaii
Re: excessive valve clearance
Cambox gaskets will settle about .002 after they are torqued and allowed to settle overnight. Since you have the head off it will be easier to do the adjustments without having to deal with the pistons contacting the valves or the timing belt skipping a tooth. With overly excessive valve clearances the cam lobe will smack the shim more violently. Damage MAY not result, but if you don't have the time now to do it the right way, when will you?